The answer is A.
Pure substance is either an element or a compound, which elements in compund is chemically combined together. They cannot be separated by physical methods such as filtration or evaporation. Compounds can only be separated by chemical methods, which include using electricity (electrolysis) or applying heat.
An sample of an unknown metal was found in a laboratory. Determining the density of the sample can help identify what type of metal is present in the sample. The sample was determined to have a mass of 27.20 g when placed on a scale. When dropped in water, it increased the volume of the water by 3.46 mL. What is the density of the sample of metal?
Use appropriate SIG FIGS in the answer.
Answer:
The answer is 2.011 *10^24
Explanation:
Looking for atoms in boron,
Molar mass of B = 10.81g/mol
There is 36.1g of B,.
Using avogadro constant = 6.023* 10^23
36.1g of B= 6.023 *10^23/10.81 * 36.1g
That is, 6.023*10^23 divided by 10.81 multiplied by 36.1g
From this calculation, we get
36.1g of boron = 2.011 * 10^24atoms.
It is expressed in inches,feet,and pounds, centimeters,meters and kilograms in the metric system.(I hope this helps)
Since the two atoms have the same number of protons they are the same element. The fact that they have different numbers of neutrons makes them isotopes. The best answer is A.
